Make ppt_record_parser.IterStream.readinto() always return desired length #715
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IterStream is derived from io.RawIOBase which is not guaranteed to return the desired bytes during read(). Unfortunately, olefile.py is expecting read() to return all bytes (except for the last sector): https://github.com/decalage2/olefile/blob/cc0bdc07194fb7dc21e75a95c9e771e5240952b2/olefile/olefile.py#L666-L676 Since IterStream implementation was already buffered, I changed readinto() to always return the desired length whenever possible.
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Found this bug while using
oleobj.pyon a PowerPoint file:The extracted embedded file was not matching the hash of the real embedded file, so I traced back the code starting from the warning message here:
oletools/oletools/oleobj.py
Lines 645 to 646 in a7d1050
The problem is that
olefile.pyis expectingread()to return all bytes (except for the last sector):https://github.com/decalage2/olefile/blob/cc0bdc07194fb7dc21e75a95c9e771e5240952b2/olefile/olefile.py#L666-L676
ppt_record_parser.IterStreamis derived from io.RawIOBase which is unfortunately not guaranteed to return the desired bytes duringread().Since
IterStreamimplementation was already buffered, I simply changedreadinto()to always return the desired length whenever possible; you might want to change that to io.BufferedIOBase